buick 231 ID ??

i have a buick 231 that i was told was a 1977. so far i have found the block cast #1261438 and the casting # was used 1976,77,78. i would like to find out if its an even fire or odd fire. i also found the numbers 231 with a 5 over it on the L side of block. i cant find any other numbers on block. i have been looking this site but still cant id it other then the year. in 1977 i also was told that some 231 even and odd fires look same (transition engines). also, i need a harmonic balancer. the one i have has come apart and i cant find one. Are the even fire and odd fire harmonic balancer interchangable? and do you need to balance the 231 even or odd with a new flywheel? any help would be great!! :?

 

From the number your block could be either odd or even, I think you'll need the cranshaft casting number to tell.

http://www.earlycj5.com/tech/engines/225/castingNumbers.shtml

I can't help on the harmonic balancers, but someone should be able too.

 

Why waste your time with the crank number Joel, if he takes the pan off he already knows if its an oddfire or evenfire. You could also take a look at the distributor guts to see if its an odd or evenfire.

 

Yep. Didn't think about the distributor guts, but I'm not sure I could tell the cranks apart if I didn't have a reference.

 

the cranks are very obvious, the odd fire are three pairs of common journal connecting rods and the even fires are three pairs of offset journal connecting rods.

JB

 

There ya go! Thanks JB!

 

Pull the distributor cap (should be HEI). If the posts look "odd" to you, it is odd fire

 

THX for the help guys. i droped the engine off @ the shop today to have a long block done. he said he would let me know odd or even when he gets it done.